1. Field of Disclosure
The present disclosure relates to a laser annealing apparatus and a laser annealing method using the same.
2. Description of the Related Art
A flat panel display device, such as a liquid crystal display device, an organic light emitting display device, etc., includes a thin film transistor to drive a pixel. The thin film transistor includes a semiconductor active layer doped with an impurity at a high concentration, and amorphous silicon or polycrystalline silicon is used for the semiconductor active layer.
The thin film transistor including the amorphous silicon has been used since it is able to be deposited with low temperature, but has disadvantages such as deterioration in reliability of electrical characteristics, difficulty in large-size display device, etc. Accordingly, in recent years, the thin film transistor including the polycrystalline silicon is widely used.
The polycrystalline silicon has a current mobility of tens to hundreds cm2/Vs, high frequency operational characteristics, and low current leakage, and thus the polycrystalline silicon is appropriate for a large-size flat panel display device. The polycrystalline silicon is fabricated by crystallizing the amorphous silicon through a laser annealing method performed by irradiating a laser beam on a thin film substrate.